A visit to the aquarium took an unexpectedly gory turn when an enormous stingray devoured its tank-mate, a helpless squid.

A video of a stingray devouring a squid in an aquarium in Japan has been retweeted over 94,000 times

Visitors at an aquarium in Japan got an uncomfortably close look at the relationship between predator and prey when a giant stingray devoured a helpless squid. A video of the incident, which we don't recommend you watch if you're particularly squeamish, was posted to Twitter on Monday and has since been retweeted over 94,000 times.

The short video begins with the enormous stingray cornering a small squid against the glass of the aquarium and promptly chomping down on it. Visitors can be heard exclaiming in horror. Some even laugh nervously.

The squid shots a jet of blue-black ink everywhere and tries desperately to free itself from its predator. Eventually, however, it disappears into the stingray's mouth.

The person filming then pans to show a number of visitors, including a little girl, looking absolutely stunned at the horror show they've just witnessed inadvertently.

On Twitter, a number of people have questioned how the incident occurred, as predators and their prey are typically kept separately in aquariums. They're also fed at regular intervals to prevent precisely such attacks.

As one person on Twitter puts it, "The food chain doesn't cease to exist in captivity. It's just what animals do."